Sandwich panel construction for structural panels typically provides high flexural stiffness and strength, and thus is used extensively in the aerospace industry, as well as various other industries. Sandwich panels are typically made with many different facesheet materials, and generally with either a foam or honeycomb core material which is sandwiched between the facesheets. Foam by itself, however, does not have an especially high level of strength and/or stiffness. Honeycomb cores, while being generally stronger than foam, can be subject to water collection. Honeycomb core materials also have other drawbacks related to consistent producibility, the ability to easily inspect such material, as well as other issues. In addition, both foam and honeycomb core types may occasionally suffer from low peel strength such that the facesheets secured to either the foam or honeycomb core tend to prematurely disbond (i.e., separate) from the foam or honeycomb core material.
Relatively low foam core strength and stiffness may be mitigated through the use of higher density foam materials. However, a weight penalty is incurred with this approach. In the aerospace industry, honeycomb core panels must be inspected regularly to identify water ingression. When water ingression is found, repair can be time consuming and costly. Low peel strength may also prevent the use of sandwich panels altogether in certain applications or, alternatively, require that higher weight, stiffened panel designs be employed.
Therefore, there is a need for a structural panel comprised of a sandwich-type construction which is structurally strong, relatively light in weight, that can be easily inspected, easily produced, and does not suffer from the various other drawbacks of traditional foam or honeycomb core structural panels.